Stable solid electrolyte interphase(SEI)has been well established to be critical for the reversible operation of Li(ion)batteries,yet our understanding of its mechanical properties currently remains incomplete.Here,we...Stable solid electrolyte interphase(SEI)has been well established to be critical for the reversible operation of Li(ion)batteries,yet our understanding of its mechanical properties currently remains incomplete.Here,we used an electrochemical quartz crystal microbalance combined with dissipation monitoring(EQCM-D)to investigate SEI formation.By quantitatively estimating in-situ,the change in mass,shear modulus,and viscosity of the SEI,we show that the SEI formation in propylene carbonate(PC)-and ethylene carbonate/diethyl carbonate(EC/DEC)-based electrolytes involves the growth of a rigid laye r followed by a viscoelastic layer,whereas a distinct"one-layer"rigid model is applicable to the SEI formulated in tetraethylene glycol dimethyl ether(TEGDME)-based electrolyte.With the continuous formation of the SEI,its shear modulus decreases accompanied by an increase in viscosity.In TEGDME,the lightest/thinnest SEI(mass lower than in PC by a factor of nine)yet having the greatest stiffness(more than five times that in PC)is obtained.We attribute this behavior to differences in the chemical composition of the SEIs,which have been revealed by tracking the mass-change-per-mole-of-electrontransferred using EQCM-D and further confirmed by X-ray photoelectron spectroscopy.展开更多
基金funding from the Natural Science Foundation of China(Nos.51761145046,21975243 and 51672262)support from the 100 Talents Program of the Chinese Academy of Sciencesthe National Program for Support of Top-notch Young Professionals,and iChEM。
文摘Stable solid electrolyte interphase(SEI)has been well established to be critical for the reversible operation of Li(ion)batteries,yet our understanding of its mechanical properties currently remains incomplete.Here,we used an electrochemical quartz crystal microbalance combined with dissipation monitoring(EQCM-D)to investigate SEI formation.By quantitatively estimating in-situ,the change in mass,shear modulus,and viscosity of the SEI,we show that the SEI formation in propylene carbonate(PC)-and ethylene carbonate/diethyl carbonate(EC/DEC)-based electrolytes involves the growth of a rigid laye r followed by a viscoelastic layer,whereas a distinct"one-layer"rigid model is applicable to the SEI formulated in tetraethylene glycol dimethyl ether(TEGDME)-based electrolyte.With the continuous formation of the SEI,its shear modulus decreases accompanied by an increase in viscosity.In TEGDME,the lightest/thinnest SEI(mass lower than in PC by a factor of nine)yet having the greatest stiffness(more than five times that in PC)is obtained.We attribute this behavior to differences in the chemical composition of the SEIs,which have been revealed by tracking the mass-change-per-mole-of-electrontransferred using EQCM-D and further confirmed by X-ray photoelectron spectroscopy.
